The present invention relates a latching device for a wing arrangement for an aircraft, which wing arrangement includes a wing comprising a base section having a first end portion adapted to be secured to the fuselage of an aircraft and an opposite second end portion, and a tip section having a third end portion and an opposite fourth end portion, wherein the third end portion is pivotably connected to the second end portion such that the tip section is pivotable about a pivot axis between a deployed position and a stowed position in which the spanwise length of the wing is smaller than in the deployed position.
The aspect ratio, i.e. the ratio of span to chord, of an aircraft wing is one factor influencing the efficiency of the aircraft during flight. Generally, an increase of the aspect ratio is associated with an increased efficiency during steady flight. Therefore, an increase of the wingspan of an aircraft is one factor to take into consideration when seeking to reduce fuel consumption. However, when elongating the wing of an existing family of aircraft, it may become necessary to adapt the aircraft family specific infrastructure, and airport fees may increase.
One possibility to increase the wingspan without having to adapt the aircraft family specific infrastructure and having to deal with increased airport fees, or to reduce airport fees for existing aircraft is to provide for a foldable wing construction which allows to pivotably move an outboard end portion of the wing between a deployed position, in which the wing has its normal flight configuration, and a stowed position, in which the wing has a folded configuration and the wingspan is decreased as compared to the deployed position. It is necessary to provide a latching device which is able to safely retain the outboard end portion in the deployed position or in the stowed position or in both positions, as long as the respective position is desired.
A latching device is disclosed for a wing arrangement having a foldable wing, which latching device is safe and reliable in operation and at the same time of a simple construction.
According to the present invention a latching device for a particular wing arrangement for an aircraft is provided.
This wing arrangement comprises a wing having a base section and a tip section. The base section has a first end portion, which is adapted to be secured to the fuselage of an aircraft, and an opposite second end portion. Thus, when the wing is mounted to a fuselage of an aircraft at its first end portion the second end portion of the base section is remote from the fuselage, i.e., a terminal end of the first end portion constitutes the inboard end of the base section and of the entire wing and an opposite terminal end of the second end portion constitutes the outboard end of the base section.
The tip section has a third end portion and an opposite fourth end portion. The third end portion is pivotably connected to the second end portion such that the tip section is pivotable about a pivot axis between a deployed position and a stowed position in which the spanwise length of the wing is smaller than in the deployed position. In other words, when two of the wings are mounted to opposite sides of a fuselage of an aircraft, the length of the shortest straight line between the outermost wingtips of the two wings is larger—and preferably maximized—in the deployed position than in the stowed position. In particular, the distance between the first end portion and the fourth end portion may be larger—and preferably maximized—in the deployed position than in the stowed position.
Thus, when the wing is mounted to a fuselage of an aircraft at its first end portion, and at least in the deployed position of the tip section, the third end portion of the tip section is spaced from the fuselage by the base section and the fourth end portion is the outermost portion of the wing, i.e., a terminal end of the third end portion constitutes the inboard end of the tip section and an opposite terminal end of the fourth end portion constitutes the outboard end of the tip section and of the entire wing.
It is to be noted that, in case the wing includes a wing tip device, the tip section may be identical to the wing tip device, but that it is preferred that the tip section comprises the wing tip device and additionally a further portion of the wing at the inboard side of the wing tip device. In this regard, in the usual manner wing tip devices are understood as devices or wing sections installed at the outermost end of a wing and being adapted to increase the effective aspect ratio of a wing without materially increasing the wingspan and to reduce drag by partially recovering the energy of tip vortices.
The latching device comprises a support structure. The support structure may, for example, be or comprise a housing or casing. Such housing or casing may preferably comprise an interior cavity and an opening at which the interior cavity is open towards an exterior of the housing.
In any case, the latching device also comprises a latching bolt having a longitudinal axis and being slidably supported by the support structure in such a manner that the latching bolt is movable between a retracted position and an extended position, wherein in the extended position the latching bolt extends further from the support structure than in the retracted position. In case of the above-mentioned examples in which the support structure is or comprises a housing the latching bolt is supported on or by the housing or casing and may preferably be received at least partially in the interior cavity.
Moreover, the latching device comprises one or more first—preferably linear—hydraulic actuators and one or more first connector assemblies adapted to be connected to a first hydraulic system of an aircraft and to supply the one or more first hydraulic actuators with pressurized hydraulic fluid. Each of the first connector assemblies may preferably include two ports for connection to two hydraulic lines. It is to be noted that each of the one or more first hydraulic actuators or some of the one or more first hydraulic actuators may have an own separate first connector assembly. However, it is preferred if the latching device has only a single first connector assembly which is common to all first hydraulic actuators, and that the pressurized fluid supplied via such common first connector assembly is distributed among the first hydraulic actuators by corresponding hydraulic lines, which are part the latching device and connected between the common first connector assembly and each of the one or more first hydraulic actuators. In any case, it is to be noted that the first hydraulic system of an aircraft mentioned above may be a hydraulic system of the aircraft which is operable to supply a plurality of consumers of the aircraft with pressurized hydraulic fluid, or may be a hydraulic system specifically provided for the latching device or for a plurality of the latching devices in a wing arrangement.
The latching device also comprises one or more second—preferably linear—hydraulic actuators and one or more second connector assemblies adapted to be connected to a second hydraulic system of an aircraft and to supply the one or more second hydraulic actuators with pressurized hydraulic fluid, i.e. hydraulic pressure. The one or more first connector assemblies are separated from the one or more second connector assemblies. Thus, the one or more first hydraulic actuators and the one or more second hydraulic actuators are thereby connectable to and operable by two separate hydraulic systems. Each of the second connector assemblies may preferably include two ports for connection to two hydraulic lines. It is to be noted that each of the one or more second hydraulic actuators or some of the one or more second hydraulic actuators may have an own separate second connector assembly. However, it is preferred if the latching device has only a single second connector assembly which is common to all second hydraulic actuators, and that the pressurized fluid supplied via such common second connector assembly is distributed among the second hydraulic actuators by corresponding hydraulic lines, which are part the latching device and connected between the common second connector assembly and each of the one or more second hydraulic actuators. In any case, it is to be noted that the second hydraulic system of an aircraft mentioned above may be a hydraulic system of the aircraft which is operable to supply a plurality of consumers of the aircraft with pressurized hydraulic fluid, or may be a hydraulic system specifically provided for the latching device or for a plurality of the latching devices in a wing arrangement.
The one or more first hydraulic actuators and the one or more second hydraulic actuators are adapted to effect movement of the latching bolt from the extended position into the retracted position independent of the other one of the one or more first hydraulic actuators and the one or more second hydraulic actuators. In other words, the one or more first hydraulic actuators are adapted and capable to effect movement of the latching bolt from the extended position into the retracted position without operation of the one or more second hydraulic actuators, and, similarly, the one or more second hydraulic actuators are adapted and capable to effect movement of the latching bolt from the extended position into the retracted position without operation of the one or more first hydraulic actuators.
The above-described latching device is of a simple construction and is nevertheless capable of providing for reliable latching of a tip section of a wing arrangement of the type likewise already described above. The latching device further provides for redundancy for the operation of the latching bolt, because each of the one or more first hydraulic actuators may be operated separately from the one or more second hydraulic actuators by connecting them to separate and different hydraulic power supplies. The latching may achieved in a simple manner by securing the support structure of the latching device to one of the tip section and the base section of the wing arrangement and by providing one or more engagement portions for the latching bolt, such as one or more bores, on the other one of the tip section and the base section in such a manner that if the tip section is in the deployed position and/or in the stowed position the latching bolt is positioned to engage or extend into a respective one of the one or more engagement portions in the extended position of the latching bolt, whereas in the retracted position of the latching bolt is disengaged from the respective one of the one or more engagement portions so as to allow for relative movement between the tip section and the base section.
In a preferred embodiment, the latching device comprises a plurality of the first hydraulic actuators and a plurality of the second hydraulic actuators. This provides for further redundancy, allows the individual hydraulic actuators to have smaller dimensions and provides the possibility to arrange the hydraulic actuators so as to decrease or minimize the risk of wedging of the latching bolt. In the latter regard, it is further preferred if the plurality of first hydraulic actuators are symmetrically arranged around the longitudinal axis of the latching bolt with an angular distance between each two adjacent first hydraulic actuators being the same, and the plurality of second hydraulic actuators are symmetrically arranged around the longitudinal axis of the latching bolt with an angular distance between each two adjacent second hydraulic actuators being the same. For example, three first hydraulic actuators with angular distances of 120° and three first hydraulic actuators with angular distances of 120° may be provided around or surrounding the latching bolt.
In a preferred embodiment, the latching device further comprises a biasing arrangement. The biasing arrangement is arranged and adapted to bias the latching bolt into the extended position and, preferably, to move the latching bolt from the retracted position into the extended position.
In this embodiment it is further preferred that the biasing arrangement comprises one or more springs, such as, e.g., one or more compression springs or one or more Belleville washers. For each of the one or more first hydraulic actuators and each of the one or more second hydraulic actuators one of these springs—or possibly more than one of these springs—is located inside a cylinder chamber of a cylinder of the respective hydraulic actuator and supported between a piston of the respective hydraulic actuator and a spring support portion of the cylinder. Alternatively or additionally, one of these springs—or possibly more than one of these springs—is located surrounding or around a portion of the latching bolt, such as, e.g., inside the interior cavity of the housing or casing if the support structure constitutes a housing or casing, and supported between a first spring support portion fixedly connected to the latching bolt and a second spring support portion which is immovable with respect to the support structure, such as a portion of the support structure. Further alternatively or additionally, one of these springs—or possibly more than one of these springs—is located inside a recess provided in the latching bolt and extending from one longitudinal end of the latching bolt and supported between a bottom of the recess opposite the longitudinal end and a spring support portion which is immovable with respect to the support structure, such as a portion of the support structure.
In any of the above-described embodiments comprising a biasing arrangement, one or more or all of the one or more first hydraulic actuators and/or one or more or all of the one or more second hydraulic actuators may be a single acting hydraulic actuator. In this case the biasing arrangement must be able to move the latching bolt into the extended position without support by the first and second hydraulic actuators.
Alternatively and additionally, and independent of whether or not a biasing arrangement is present, one or more or preferably all of the one or more first hydraulic actuators and/or one or more or preferably all of the one or more second hydraulic actuators is a double acting hydraulic actuator. The one or more first double acting hydraulic actuators and the one or more second double acting hydraulic actuators are then adapted to be operable to exert a force to the latching bolt to effect movement of the latching bolt from the retracted position into the extended position (or at least assist such movement, if a biasing arrangement is present which is adapted to effect this movement together with the one or more first double acting hydraulic actuators or the one or more second double acting hydraulic actuators) independent of the other one of the one or more first double acting hydraulic actuators and the one or more second double acting hydraulic actuators. In other words, the one or more first double acting hydraulic actuators are adapted and capable to effect (or at least assist) movement of the latching bolt from the retracted position into the extended position without operation of the one or more second double acting hydraulic actuators, and, similarly, the one or more second double acting hydraulic actuators are adapted and capable to effect (or at least assist) movement of the latching bolt from the retracted position into the extended position without operation of the one or more first double acting hydraulic actuators. Provided that the one or more first double acting hydraulic actuators are adapted and capable to effect movement of the latching bolt from the retracted position into the extended position and the one or more second double acting hydraulic actuators are adapted and capable to effect (or at least assist) movement of the latching bolt from the retracted position into the extended position, the latching device does not require a biasing arrangement. Nevertheless, the biasing arrangement may still be provided for prepositioning the latching bolt and/or to supplement the action of the first and second double acting hydraulic actuators.
It is to be noted that it is in principle also possible to have, instead of one or more first and second double acting hydraulic actuators and in addition to the one or more first single acting hydraulic cylinders and the one or more second single acting hydraulic cylinders one or more third single acting hydraulic cylinders and one or more fourth single acting cylinders, which are adapted to effect (or at least assist) the movement of the latching bolt from the retracted position into the extended position in the manner described above for the one or more first double acting hydraulic cylinders and the one or more second double acting hydraulic cylinders. These third and fourth hydraulic cylinders would then be connected to the one or more first connector assemblies and the one or more second connector assemblies, respectively. However, such separate single acting hydraulic actuators require additional space, so that the provision of double acting hydraulic actuators is preferred.
In a preferred embodiment, the latching bolt comprises or is fixedly attached to one or more hydraulic actuator engagement portions, each of which is extending transversely, and preferably—at least with a part thereof—perpendicularly, with respect to the longitudinal axis. Each of the one or more first hydraulic actuators and each of the one or more second hydraulic actuator engages or is secured to at least one the one or more hydraulic actuator engagement portions—and preferably to the perpendicularly extending part thereof, if present—to thereby effect the movement of the latching bolt from the extended position into the retracted position, and possibly, as the case may be, also from the retracted position into the extended position, upon actuation of the one or more first hydraulic actuators or the one or more second hydraulic actuators, as described in detail above.
In a preferred embodiment, the latching device further comprises one or more locking mechanisms—and possibly two or more for reasons of redundancy—each having a locking element which is selectively movable between a locking position and an enabling position. Each such locking mechanism and the corresponding locking element are configured and arranged such that when the latching bolt is in the extended position and the locking element is moved from the enabling position to the locking position the locking element engages the latching bolt or a component secured thereto and prevents the latching bolt from moving out of the extended position. Conversely, when the latching bolt is in the extended position and the locking element is moved from the locking position to the enabling position it no longer prevents the latching bolt from moving from the extended position into the retracted position. The locking element may be or comprise, e.g., a cam element connected to a rotatable shaft, i.e., the locking mechanism comprises a rotatable shaft with a radially extending projection constituting or forming part of the locking element. For example, the rotatable shaft may extend transversely and preferably perpendicularly with respect to the longitudinal axis of the latching bolt such that it is spaced from an end face of a longitudinal end of the latching bolt or a component secured to the longitudinal end of the latching bolt, both in the retracted and in the extended position of the latching bolt. This longitudinal end is the longitudinal end, which moves away from the rotatable shaft when the latching bolt moves from the retracted position into the extended position. The cam element or projection is then arranged such that upon rotation of the rotatable shaft in the extended position of the latching bolt, the cam element or projection “fills” the gap between the end face of the latching bolt or the component and the rotatable shaft and abuts the end face of the latching bolt or the component, such that the latching bolt is prevented from moving out of the extended position. Advantageously, locking and unlocking of the latching bolt may then be effected by rotating the rotatable shaft in a single direction only. If the locking mechanism comprises a rotatable shaft, the latching device then preferably also comprises one or more bearings for the rotatable shaft.
In the above embodiments, in which the latching device comprises one or more locking mechanisms, it is further preferred if each of these locking mechanisms further comprises a—preferably hydraulically or electrically powered—locking actuator operable to move the locking element between the locking position and the enabling position, and preferably both from the locking position into the enabling position and from the enabling position into the locking position. Preferably, for reasons of redundancy each locking mechanism comprises two of these locking actuators, which are adapted to independently effect the above movement or movements of the locking element, e.g. two locking actuators which are independently able to effect rotation of the rotatable shaft in the above-described example of a locking mechanism including a rotatable shaft.
It is to be noted that a separate locking arrangement is not be necessary and may be dispensed with if the above-described biasing arrangement is present and is adapted to be sufficiently strong to retain the latching bolt in the extended position under the intended operating conditions of the latching device.
In accordance with the purpose of the above-described latching device, one or more of the latching devices may be part of a wing arrangement for an aircraft. The wing arrangement is of the construction already described in detail above. Thus, to summarize briefly, it comprises a wing comprising a base section having a first end portion adapted to be secured to the fuselage of an aircraft and an opposite second end portion, and a tip section having a third end portion and an opposite fourth end portion, wherein the third end portion is pivotably connected to the second end portion such that the tip section is pivotable about a pivot axis between a deployed position and a stowed position in which the distance between the first end portion and the fourth end portion is smaller than in the deployed position. For further details, reference is made to the above extensive explanations.
The first connector assembly of each of the one or more latching devices is connected or connectable to a first hydraulic system of an aircraft and the second connector assembly of each of the one or more latching devices is connected or connectable to a second hydraulic system of an aircraft. In this regard it is to be noted that the first hydraulic system of an aircraft and the second hydraulic system of an aircraft may be a hydraulic system of an aircraft adapted to supply a plurality of consumers of the aircraft with pressurized hydraulic fluid, or may be a local hydraulic system provided as part of the wing arrangement, which local hydraulic system locally generates or provides hydraulic pressure, for example, via an electric motor and a hydraulic pump. Of course, it is also possible that the first hydraulic system is of one of these types and the second hydraulic system is of the other of these types.
In any case, for each of the one or more latching devices, the support portion of the respective latching device is secured to one of the second end portion and the third end portion and the other of the second end portion and the third end portion comprises one or two bores, i.e. a first bore and/or a second bore.
Each of these bores is arranged such that in the deployed position of the tip section the respective bore is aligned with the latching bolt of the respective latching device such that the latching bolt is movable into engagement with the respective bore by moving it into the extended position and out of engagement with the respective bore by moving it into the retracted position, or such that in the stowed position of the tip section the respective bore is aligned with the latching bolt of the respective latching device such that the latching bolt is movable into engagement with the respective bore by moving it into the extended position and out of engagement with the respective bore by moving it into the retracted position. It is then possible that separate ones of the latching devices are utilized for latching the tip section in the deployed position and in the stowed position, wherein for one or more of the latching devices the respective bore is aligned with the latching bolt in the deployed position of the tip section and for one or more different ones of the latching devices the respective bore is aligned with the latching bolt in the stowed position of the tip section. It is also possible that the latching device or devices are only arranged and operable to latch the tip section in the deployed position, and that separate means must be provided for latching the tip section in the stowed position.
In case of two of such bores, i.e. if a first and a second bore are present for each of the one or more latching devices, the first bore and the second bore are arranged such that in the deployed position of the tip section the first bore is aligned with the latching bolt of the respective latching device such that the latching bolt is movable into engagement with the first bore by moving it into the extended position and out of engagement with the first bore by moving it into the retracted position, and in the stowed position of the tip section the second bore is aligned with the latching bolt of the respective latching device such that the latching bolt is movable into engagement with the second bore by moving it into the extended position and out of engagement with the second bore by moving it into the retracted position. This arrangement is particularly advantageous because the latching device or devices are adapted to effect latching in both the deployed and stowed positions, so that the total number of latching devices required as part of the wing arrangement may be reduced.
In any case, for each of the latching devices, when the latching bolt is in engagement with one of the one or two associated bores it prevents movement of the tip section out of the deployed position or the stowed position, as the case may be. Thus, with a single associated bore, i.e. a first bore or a second bore, it prevents movement of the tip section out of the deployed position or out of the stowed position, depending on the position of the respective bore. If two bores are present, i.e. a first bore and a second bore, the latching bolt prevents movement of the tip section out of the deployed position when the latching bolt is in engagement with the first bore, and the latching bolt prevents movement of the tip section out of the stowed position when the latching bolt is in engagement with the second bore. The latching bolt may have a tapered design or a tapered tip portion in order to facilitate entry of the latching bolt into the associated bore or bores and to provide for some degree of self-alignment.
In a preferred embodiment the wing arrangement comprising two or more of the latching devices for the deployed position of the tip section or for both the deployed and stowed positions of the tip section, for reasons of redundancy. Then the latching bolts of the latching devices and the associated bores may be dimensioned such that in each of these positions only one or only some of the latching bolts have a diameter matching the diameter of the associated bore or bores in the extended position of the latching bolt, whereas another one or others of the latching bolts have diameters smaller than the associated bore or bores. The first-mentioned latching bolt or bolts then constitute a primary latching bolt or primary latching bolts, and the latter latching bolt or bolts then constitute a primary latching bolt or secondary latching bolts. Unless the primary latching bolt or bolts fail, the secondary latching bolt or bolts do not carry load and only become responsible for the latching in case the primary latching bolt or bolts fail. In this way a more exact definition of the load path may be implemented.
The wing arrangement according to any of the above-described embodiments may be part of an aircraft. The aircraft further comprises a fuselage, wherein the first end portion of the base section is attached to the fuselage and the base section is arranged between the fuselage and the tip section, and a first hydraulic system and a separate second hydraulic system, i.e. the second hydraulic system is independent or not in fluid communication with the first hydraulic system. Each of the first and second hydraulic systems may be a hydraulic system which is adapted and operable to supply a plurality of consumers of the aircraft with pressurized hydraulic fluid or may be a hydraulic system specifically provided for the latching device or for a plurality of the latching devices in the wing arrangement—and possibly also for other consumers in the wing arrangement, but not for consumers outside the wing arrangement. In the latter type of hydraulic system the hydraulic pressure may be provided, e.g., by a motor driving a hydraulic pump.
In any case, the one or more first connector assemblies of the one or more first hydraulic actuators are connected to, i.e. in fluid communication with, the first hydraulic system and the one or more second connector assemblies of the one or more second hydraulic actuators are connected to, i.e. in fluid communication with, the second hydraulic system.
In a preferred embodiment the first hydraulic system is operable to supply a plurality of consumers of the aircraft with pressurized hydraulic fluid, and the second hydraulic system is operable to supply a plurality of consumers of the aircraft with pressurized hydraulic fluid.